Exchangeable slip-on reinforcement for a press roller base body on spinning machine drawing frames

ABSTRACT

An exchangeable reinforcing element for pressure rollers of drafting units of spinning machines. The reinforcing element comprises a thin reinforcing tube and a flexible roller covering securely affixed thereto which can be slid onto the pressure roller base body. The reinforcing element is cut from a long tube body to the required effective width. The roller covering is turned down at both ends in such a way that the reinforcing tube projects laterally over the roller covering.

This application is a national phase application of International application PCT/EP2004/003332, filed Mar. 30, 2004 and claims the priority of German application No. 10 320 526.8, filed Apr. 30, 2003, the disclosure of which are expressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to an exchangeable reinforcing element which can be slid onto pressure roller base bodies of drafting units of spinning machines, which reinforcing element comprises a thin reinforcing tube and a flexible roller covering having a running surface for fiber material, the flexible roller covering being attached securely to the reinforcing tube.

Today spinning processes involving drafting units permit a spinning speed of several hundred meters per minute. This applies to the process of so-called airjet spinning. In the case of such spinning aggregates, high demands are made on the drafting units arranged upstream. The delivery rollers of high-speed drafting units can rotate at 7,000 rpm.

At such speeds, the roller coverings of the pressure rollers are worn out in a very short time. The roller coverings of the pressure rollers of the delivery roller pair have to be repolished after an operational running time of between 3 to 5 days. Pressure rollers, however, can only be polished a maximum of five times, as the diameter of the roller coverings then becomes too small. The roller coverings of such pressure rollers are today therefore exchangeable, whereby on the pressure roller base bodies of spinning machine drafting units, a slideable reinforcing element is provided, which comprises a thin reinforcing tube, mostly consisting of an aluminum alloy, with which reinforcing tube a flexible roller covering is securely attached, for example by means of vulcanization. The roller covering comprises the actual running surface for the fiber material. In practice, the exchangeable reinforcing element, consisting of the reinforcing tube and the roller covering, is produced today as a long tubular body, which can then be cut to the necessary effective width by means of cutting off. The cut off reinforcing element can then be pressed onto the respective pressure roller base body after a minimum amount of re-working.

An exchangeable reinforcing element comprising a reinforcing tube and a flexible roller covering securely attached thereto of the above mentioned type is, for example, prior art in the German published patent application 20 61 434 or the U.S. Pat. No. 6,237,196. In the case of these reinforcing elements, and due to the cutting out from a long tubular body, the width of the roller covering measures the same as the width of the reinforcing tube. This results, because of this design, in several disadvantages, as contrary requirements should be met simultaneously. On the one hand, the reinforcing element should be as narrow as possible, so that the roller covering of the delivery roller pair of a drafting unit can exert the necessary pressure on the fiber material, while on the other hand the reinforcing element should be wide enough to cover the lateral bearing area of the pressure roller base body of the reinforcing tube, so that the penetration of fibers and thread ends in the bearing area is prevented.

A non-generic prior art is known from the German published patent 908 459, in which the roller covering is narrower than the reinforcing tube. With the aid of such a reinforcing element, the above mentioned disadvantages could be overcome, but said prior art comes from a time in which the reinforcing elements were not cut out from a long tubular body and then cut to the required effective width. Rathermore, a reinforcing tube was made in the required width and subsequently the roller covering was vulcanized thereon. The fact that the roller covering is hereby narrower than the reinforcing tube, is a result of said special manufacturing process.

It is an object of the present invention to create an exchangeable reinforcing element of the above mentioned type made from a long tubular body, whereby it is possible in spite of this to meet the above mentioned contrary demands.

This object has been achieved in accordance with the present invention in that the roller covering at both end areas is turned down in such a way that the reinforcing tube projects laterally out over the roller covering.

The basis for the present invention is, as in the above mentioned prior art, a tube-like semi-finished product, which is cut to the necessary effective width. The roller covering is subsequently made narrower than the reinforcing tube. Thus the two contrary requirements are met, namely on the other hand to obtain a high nipping pressure but on the other hand to create a sufficiently long sealing gap for the bearing area of the pressure roller base body. In addition, there is the great advantage that because of the turning down of the roller covering at its end areas, an enlarged metal surface is created on the surface of the reinforcing tube, over which the heat occurring during operation can dissipate quickly and effectively.

The lateral turning down of the roller covering does not need to take place after the cutting to the required effective width, but rather can be carried out before the cutting out. In the latter case, a reinforcing element is delivered whereby the reinforcement tube is already wider than the roller covering. A short re-working at the respective front surface is then all that is required.

The described advantages can also be attained for a reinforcing element according to the above mentioned prior art alternatively in that supplementary rings, in contact with the reinforcing tube, but without a roller covering, and having the same inner diameter as the reinforcing tube, are arranged to the reinforcing element at both front ends of the reinforcing tube. In this case, the roller covering does not have to be made narrower than the reinforcing tube through re-working, but rather the two supplementary rings are disposed laterally on the reinforcing tube, which rings both have essentially the same diameter dimensions as the reinforcing tube. In this way also a relatively narrow roller covering having a high nipping pressure is created, while at the same time, via the supplementary rings, which cover the bearing areas, the heat dissipates, as the supplementary rings have direct contact with the reinforcing tube.

For this purpose, the reinforcing tube has a slightly smaller outer diameter on its areas which project laterally over the roller covering im comparison to its middle area which is covered by the roller covering. When the roller covering is turned down, a very small shoulder arises, which measures approximately 0.1 mm. With the above mentioned measure, the concentric running of the reinforcing element is improved, as not only is the polished roller covering but also the projecting areas of the reinforcing tube have been treated.

In an embodiment of the present invention, the reinforcing tube, or in the case of supplementary rings, the latter can be provided on its front end areas with a slightly enlarged inner diameter. The inner diameter, increased hereby by approximately 0.5 mm, then forms a narrow sealing gap, measuring between, for example, 0.2 mm and 0.3 mm, with an outer ring arranged to the bearings, which sealing gap is adapted exactly to the present conditions. The enlarged inner diameter also permits a small shoulder on the outer collar of the bearing outer ring, which shoulder prevents loose fibers from getting into the sealing gap.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings for example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a larger than actual size depiction of a cut side view of an air-jet aggregate and a drafting unit arranged upstream therefrom,

FIG. 2 is an embodiment of the present invention illustrating a pressure roller of the delivery roller pair of the FIG. 1_drafting unit, comprising a reinforcing element in axial section,

FIG. 3 illustrates the exchangeable reinforcing element for the pressure roller according to FIG. 2,

FIG. 4 illustrates an unfinished reinforcing element cut to the required effective width before the lateral turning down of the roller covering,

FIG. 5 is a smaller than actual size depiction of a long tubular body, out of which unfinished individual reinforcing elements may be punched,

FIG. 6 is an embodiment similar to FIG. 1, in which supplementary rings are disposed laterally on the reinforcing element,

FIG. 7 is a much larger than actual size depiction of a section of FIG. 2 identified by the dot-dash circle VII.

DETAILED DESCRIPTION OF THE DRAWINGS

The arrangement shown in FIG. 1 serves the manufacture of a spun thread 1 from a staple fiber stand 2. The arrangement comprises as essential components a spinning machine drafting until 3 as well as an air-jet aggregate 4. The following description of this arrangement simply serves to demonstrate the actual application of the present invention, described below.

The staple fiber strand 2 to be spun according to FIG. 1 is fed to the drafting until 3 in feed direction A and withdrawn as a spun thread 1 in delivery direction B and guided onwards to a winding device (not shown).

The only partly shown drafting until 3 is designed preferably as a three-cylinder drafting unit and comprises overall three roller pairs, which each comprise a driven bottom roller and a pressure roller flexibly pressed thereagainst. A roller pair 5,6 is arranged downstream of a front roller pair (not shown), said roller pair 5,6 being provided with guiding aprons 7 and 8, as well as a delivery roller pair 9,10. The driven bottom rollers are denoted by the reference numbers 5 and 9, while the reference numbers 6 and 10 denote the pressure rollers belonging thereto. In a drafting unit 3 of this kind, the staple fiber strand 2 is drafted in the known way to the desired degree of fineness. Directly downstream of the drafting unit 3, a thin fiber band 11 is present, which is drafted by still twist-free.

The air-jet aggregate 4, which imparts the spinning twist and is arranged at a close distance downstream of the drafting unit 3, can in principal be designed as required in the present invention, whereby, however, those designs which permit particularly high delivery speeds are preferred.

The fiber band 11 is fed to the air-jet aggregate 4 via an entry channel 12. Downstream therefrom is a so-called vortex chamber 13, in which the fiber band 11 is imparted the spinning twist, so that the spun thread 1 forms, and is withdrawn through a yarn withdrawal channel 14.

A fluid device generates a vortex current in the vortex chamber 13 by means of blowing in pressurized air through air-pressure jets, which are arranged tangentially in the vortex chamber 13. The pressurized air exiting from the jet openings is guided off through an air evacuation duct 15, whereby this duct 15 comprises a ring-shaped cross section around a spindle-shaped stationary component 16, which comprises the withdrawal channel 14.

In the area of the vortex chamber 13, a twist block, in the form of an edge of a fiber guiding surface, is arranged, which guiding surface is arranged slightly eccentric to the yarn withdrawal channel 14 in the area of its entry opening.

In the arrangement, the fibers to be spun are held on the one hand in the fiber band 11 and are thus fed from the entry channel 12 essentially without twist into the yarn withdrawal channel 14. On the other hand the fibers are subject to the effect of the vortex current in the area between the entry channel 12 and the yarn withdrawal channel 14, which current causes them or least their end areas to be radially driven away from the entry opening of the yarn withdrawal channel 14. The threads 1 produced by the described process possess a core of fibers of fiber areas extending essentially in thread longitudinal direction without any essential twist, and an outer area, in which the fiber and fiber areas are wrapped around the core.

Basing the formation of the thread structure on an idealized process for the purposes of greater clarity, it can be said that the structure of the thread 1 forms because the front running ends of the fibers, in particular those whose rear areas are held upstream by the feed channel 12, essentially reach the yarn withdrawal channel 14 directly, whereas the fiber areas following behind, in particular when they are no longer held in the entry area of the feed channel 12, are pulled out of the staple fiber band 11 due to the rotating air current and then are twisted around the formed thread 1. In any case, fibers are bound into the forming thread 1, whereby they are pulled through the yarn withdrawal channel 14, and are simultaneously subject to the effects of the vortex current, which centrifugally accelerates the fibers, that is from the inlet opening of the yarn withdrawal channel 14 onwards, from where they are sucked into the air evacuation duct 15. The fiber areas pulled out of the fiber band 11 because of the vortex current from a fiber vortex, the so-called sun, which projects into the entry opening of the yarn withdrawal channel 14, the longer parts of which wind, helix-like outside around the spindle-shaped entry area of the yarn withdrawal channel 14 and are pulled in this helix against the force of the current in the air evacuation duct 15 against the entry opening of the yarn withdrawal channel 14.

An arrangement of this type permits particularly high spinning speeds, which can lie in the order of magnitude of 600 m per minute. It is clear that very high demands are made hereby on the drafting unit 3, because the delivery roller pair 9,10 has to travel very fast due to the necessary high draft performance. This results inevitably in the roller coverings 20 of the pressure rollers 10 wearing at a fast rate and having to be replaced.

As already mentioned, the roller coverings 20 must be ground again after an operational time of only a few days, which can occur a maximum of five times altogether. Thereafter, the outer diameter of the roller covering 20 becomes too small.

As can be seen in FIG. 1, the pressure roller 10 of the delivery roller pair 9, 10 comprises a pressure roller base body 17 and a reinforcing element 18, which is exchangeable. The reinforcing element 18 comprises a reinforcing tube 19 and the roller covering 20 with its running surface 21 for the fiber material. During the exchange, the reinforcing element 18 is removed from the base body 17 by means of a suitable removal device and replaced by a new reinforcing element 18, which is pressed onto the old base body 17.

In FIG. 2 the pressure roller 10 of the delivery roller pair 9,10 is shown in axial section. The base body 17, also the reinforcing element 18, which comprises the reinforcing tube 19 and the roller covering 20 as well as the running surface 21, can be seen.

The axle 22 of the pressure roller 10 is supported laterally in anti-friction bearings 23 and 24, which are each covered by a cover 25,26, which at the same time comprises the bearing outer ring. A sealing gap 27 can be seen between the reinforcing tube 19 and the respective cover 25 and 26, which sealing gap 27 is described below in more detail with the aid of FIG. 7.

As can be seen, the roller covering 20 is so turned at both end areas 28 and 29 that the reinforcing tube 19 projects laterally over the roller covering 20. Thus seemingly contrary requirements can be met, namely in that on the one hand, because of the narrow roller covering 20 on the delivery roller pair 9,10, a high nipping pressure is achieved, and on the other hand, in that, despite this, a sufficiently wide reinforcing tube 19 is present which covers over the lateral covers 25,26 with a sealing gap 27. In addition, at the ends of the reinforcing tube 19, areas occur which are no longer covered by the roller covering 20, so that in these areas the heat, which occurs to a high degree during operation, can be dissipated quickly and thus be prevented from reaching the anti-friction bearings 23 and 24.

In FIG. 3, the exchangeable reinforcing element 18, on which the actual present invention is based, is shown separately. This reinforcing element 18 is replaced entirely in the case of wear of the roller covering 20, as soon as it cannot be ground any more, that is, together with the reinforcing tube 19. By turning the roller covering 20 at its end areas 28 and 29, a state is achieved in which the reinforcing tube 19 is wider than the roller covering 20, out of which the above mentioned advantages arise. It can be seen further that lateral bevels are applied to the roller covering 20 and bevels 31 are applied to the reinforcing tube 19 in the area of their front ends, after the entire reinforcing element 18 has been delivered.

FIG. 4 shows the delivered semi-finished state 32, from which the reinforcing element 18 is made by subsequent machining. This semi-finished state 32 is cut to an effective width c and comprises an as yet still unworked reinforcing tube 33 as well as an unworked roller covering 34.

FIG. 5 shows, in smaller than life-size dimensions, tube rounds for the long tube bodies 35, out of which the individual reinforcing elements 18 will be made. A tube jointing sleeve 36, sufficiently long for a plurality of pressure rollers 10, is provided with an equally long covering 37, which is attached securely to the tube jointing sleeve 36, for example by means of vulcanization. This tube body 35 is subsequently cut to the necessary effective width c, namely by means of cutting at those places denoted by dot-dash lines. Thus the semi-finished product 32 occurs as shown in FIG. 4.

In contrast to the procedure described above, the covering 37 can, of course, be turned down in advance at those places, at which the tube body 35 is to be cut out. As a result, only the tube jointing sleeve 36 needs to be cut to the required effective width c, while the covering 37 is already as narrow as it subsequently needs to be as shown in FIG. 2.

FIG. 4 shows a variation which is also created from a long tube body 35 according to FIG. 5, for which, however, a reinforcing element 18′ is provided, whose roller covering 20′ has the same width as the reinforcing tube 19′. Thus a reinforcing element 18′ is applied which has a narrower effective width e than previously described.

According to FIG. 6, not only the reinforcing element 18′ is pressed onto the base body 17, but also laterally adjacent thereto and in addition thereto supplementary rings 38 and 39, whose inner diameter d corresponds to the inner diameter of the reinforcing tube 19′. The supplementary rings 38 and 39 are disposed flush with the front surface of the reinforcing tube 19′ so that the heat from the reinforcing tube 19′ can be transferred to the supplementary rings 38 and 39 and from there dissipated into the atmosphere. This design also permits a pressure roller 10 on which the roller covering 20′ is sufficiently narrow to achieve a high nipping pressure, while at the same time covering the anti-friction bearings for the purposes of a sufficient sealing gap 27 and a reliable carrying off of heat.

FIG. 7 shows, greatly enlarged, that area of FIG. 1 which is denoted by a dot-dash circle.

Sections of the base body 17 can be seen, as well a reinforcing element 18, which comprises a reinforcing tube 19 and a narrower, that is re-worked roller covering 20. The roller covering 20 is again provided with a bevel 30. The above mentioned cover 26 comprising a bearing outer ring covers over an anti-friction bearing 24.

Due to the turning down of the roller covering 20, a laterally projecting area 40 without a roller covering occurs on the reinforcing tube 19. The outer diameter of this area 40 is slightly smaller than the outer diameter of the reinforcing tube 19 in the middle area, which is covered by the roller covering 20. The small shoulder 41 arising herefrom is however only approximately 0.1 mm high.

The front side end area 42 of the reinforcing tube 19 is re-worked in such a way that the reinforcing tube 19 after the re-working process has a slightly enlarged inner diameter. The inner diameter in the front side end area 42 is approximately 0.5 mm larger than in the middle area of the reinforcing tube 19. Because of these measures, a small shoulder 43 measuring between 0.2 to 0.3 mm in height is applied to the above mentioned cover 26 at that place which is arranged to the front side end area 42 of the reinforcing element 19, which creates a very exactly defined sealing gap 27 measuring approximately between 0.2 and 0.3 mm. The shoulder 43 is important for keeping wandering fiber material from reaching the sealing gap 27 in the first place.

The front side end area 42 is sufficiently long to permit the heat occurring during operation to be carried off from the reinforcing tube 19, without the carrying-off of heat being prevented by the roller covering 20.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

1-4. (canceled)
 5. An exchangeable reinforcing element mountable on a roller base body of a drafting unit of a spinning machine, comprising: a reinforcing tube; and a flexible roller covering having a running surface for fiber material, wherein the flexible roller covering is concentrically located on an outer surface of the reinforcing tube, and the flexible roller covering is trimmed at its axial end areas such that the reinforcing tube projects axially beyond the axial end areas of the flexible roller covering.
 6. A reinforcing element according to claim 5, wherein the reinforcing tube, in its areas which project axially beyond the axial end areas of the flexible roller covering, has a slightly smaller outer diameter than in a middle area of the reinforcing tube covered over by the flexible roller covering.
 7. An exchangeable reinforcing element mountable on a roller base body of a drafting unit of a spinning machine, comprising: a reinforcing tube; a flexible roller covering having a running surface for fiber material; and supplementary rings, wherein the flexible roller covering is concentrically located on an outer surface of the reinforcing tube, the flexible roller covering and the reinforcing tube have the same axial length, the supplementary rings and the reinforcing tube have the same inner diameter, and the supplementary rings are coaxially located adjacent to axial ends of the reinforcing tube.
 8. A reinforcing element according to claim 5, wherein at its axial ends, the reinforcing tube is provided with an inner diameter which is slightly larger than an inner diameter at a middle of the reinforcing tube.
 9. A reinforcing element according to claim 6, wherein at its axial ends, the reinforcing tube is provided with an inner diameter which is slightly larger than an inner diameter at a middle of the reinforcing tube.
 10. A reinforcing element according to claim 7, wherein the supplementary rings are provided at their axial end areas with an inner diameter which is slightly larger than an inner diameter at a middle of the reinforcing tube. 